Building Lean Systems 5 S VANVA Ardavan AsefVaziri
Building Lean Systems 5 S, VA/NVA Ardavan Asef-Vaziri
The Read Cost of Inventory p p p Has cost – Physical carrying costs – we need storage and human resources. – Financial costs (Opportunity Cost) – We could have invested our capital elsewhere and benefit from it. In the LFT Game financial cost is 10% of the cost of goods. Has risk of obsolescence – Due to change in customer preferences, and due to technological changes. Hides problems – Even if we produce low quality product, there is enough inventory downstream. – Untrustworthy suppliers, machine breakdowns, long changeover times, too much scrap do not show up. – Long flow time, Feedback loop is long. not-uniform operations. Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 22
Enable Flow: River Analogy A "river and rocks" analogy likens the water level to the inventory level in a facility. A higher water level hides potential blemishes in the process. As the water level is lowered, these problems surface, forcing management to correct. The key is to resist to reduce the inventory level too quickly. Lower the water level a little, break apart the exposed rocks (obstacles), and then lower the water level once again. Scrap Capacity Imbalances Large Setup Times Unreliable Suppliers Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 33
The Lean System p As attempts are made to reduce inventory levels, other major elements that should be in place are n n n p p Reliable processes Preventive maintenance systems Cross-trained workers Setup reduction programs Reliable suppliers. Partnership with supplies, schedule visibility If these are not already present in a factory, putting them in place takes time-it cannot happen overnight. The Japanese spent bout 20 years perfecting the system before the US automakers observed TPS. Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 44
The Lean System p For the boat to move faster, all the oars should be in the water at the same time. n n p Balance the flow across the supply chain Have all processes working at the same rate Having some resources working faster than others will pile up inventory. Making sure all resources respond to pull signals ensures a smooth flow of products across the enterprise, or the supply chain. Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 55
The important lean thinking tools to promote flow p p p p 5 S Flow Chart the Process Value- and non-value added activities Takt Time Average Labor Content, and minimum manpower Mixed Model Scheduling One Piece Flow Cellular Layout Standard Work Pull Replenishment: Placing a cap on WIP Point-Of-Use Material Storage Mistake Proofing and Method sheets Continuous Improvement and the Pursuit of Perfection Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 66
The Toyota Production System (TPS) & JIT p TPS & JIT n n n p Kanban Layout of The Plant – U-Shape Cells, a person serves more than one machine, better communications of workers Kaizen Moving Assembly Line Supermarket Operations Waste Reduction The Outcome n JIT Every step should work in harmony Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 77
How to Implement p p The goal of lean is to transform inputs into outputs faster; a leter that reaches its destination more quickly. No waiting, no delay. Question n n p Implement lean on all processes and activities or first focus on a subset? Implement lean on all products or first on a subset? Answer: Choose one product family at a time and implement lean on all the processes and activities that apply to that product family before moving on to the next product family. Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 88
5 S: A systematic process for organizing the workplace Japanese Definition English Example Seiri Tidiness. Throw Away Rubbish. Sorting Items are classified as Necessary, Unnecessary (disposed of immediately), Red tag (auctioned for anyone to claim as necessary). No claim discarded Seiton Organization. Retrieve in 30 seconds Storing Arrange items in order so that they can be picked up easily. Visual information about what & how much should be stored in a spot. Tools are hung on boards, with a silhouette (shadow box) of the tool painted. Drawers have Styrofoam cutouts of the items to be stored. Seiso Cleanliness. keeping the area clean, and organized. Sanitizing Individual Responsibility. Not just sweeping the floor and cleaning up leaks and spills. Checks for malfunctioning machinery or loose parts on machines. If machines are kept clean, oil leaks will be discovered before a equipment failure. If aisles are clean, accidents are minimized, etc. Seiketsu Neatness. Standardizing Standards by which personnel must measure and maintain personal and environmental "cleanliness. " What the normal condition should be. How an abnormal condition should be corrected. Visual management; by color-coding and standardization of colors for easier identification of problems. Personnel are trained to detect such problems using one or more of their five senses and to correct them immediately. Shitsuke Discipline Sustaining Do 5 S Activities Daily and continually Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 99
Identify Value & Non-Value Added Activities p Value added; An activity that adds value to the product in the eyes of the customer. Non-Value added: any thing else. p Identifying p p and reducing NVA activities is key to streamlining a process. The Value added ratio. Total VA time divided by the total process time. While the it depends on the industry, a ratio of 10% is suggested. It is 1. 8% in the next flow chart. It indicates the amount of waste and opportunities for lean efforts to remove waste. Process flow chart captures the logical sequence of activities to eliminate NVA activities. Spaghetti diagram depicts the physical movement of products the extent of travel, and back-tracking. To come out with a better layout. The process flow chart should be drawn after 5 S. If before, lack of attention to simple housekeeping activities may obfuscate some of the NVA activities. For instance, the operators could be taking more time to change tooling simply because they cannot find the tools, and that may be reflected in the time standards set for tool changeover. Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 10 10
Process Flow Chart and Spaghetti Diagram Lean Thinking: 2 - Enabling Flow, A. Asef-Vaziri, Systems & Operations Management. 11 11
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